Induction-coil for ignition systems.



B. L. LAWTUN.

INDUCTIGN COIL FOR IGNITION SYSTEMS.

APPLICATION FILED JAN. 25. 1909. 4 928,204. Patented July 13, 1909.

l 45 single case.

UNITED 1- sTATEs PATENT oEEIoE.

BURTON LVL LAWTON, OF MERIDEN, CONNECTICUT, ASSIGNOR TO THE UNIT COIL COMPANY,

` A CORPORATION OF NEW JERSEY.

INDUCTION-COIL FOR IGNITION SYSTEMS.

Speci'cation of Letters Patent.

Patented July 13, 1909.

l Original application led J'une 19,1907, Serial No; 379,782. Divided and this application filed January 25, 1909.

- Serial No. 474,032.

To all whom fit may concern:

Beit known that I, BURTON L. LAw'roN, 'a citizen of the United States, residing at Meriden, in the county of New Haven and 5 State .of Connecticut, have invented certain new and useful Im rovements in Induction- Coils for Ignition ystems, of which the following is a specification.

This ap lication is a division from my application erial Number 37 9,7 32 filed June 19, 1907, Patent No. 911,414, dated Feb. 2, 1909. That patent relates to a multiple cylinder internal combustion motor i ition system and this present application re ates to the induc-y tion coil ap aratus to be used in such a s stem. In igh tension ignition systems of t iscliaracter it is desirable to provide primary arid secondary windings to correspond with theigniters in the cylinders. I prefer to supply all'the primary windin s from a common source such as a attery o dry cells and to provide an individual vibrator for cach primary. The secondary of each coilis preferably'wound on the same core with itsl primary. A circuit 'closer -brings the rimaries successively into circuit. The vi rators then act so as to interrupt the circuits rapidly and induce momentary currents in the corresponding secondaries suiicient for. 1t1on. v Four cycle motors have one 1gn1' tlon and working stroke of each piston once in two complete revolutions of the main shaft. four cylinder engine, therefore has one ignition at each half revolution of the main shaft.- There is, therefore, at the moment of ignition in one cylinder, some other cylinder with a full charge of air and fuel, but uncompressed. This charge is inammable and sometimes is untimely ignited, especiallywhen the mixture is rich.

For convenience in manufacture, shipping,

handling, installing, operating, test-ino', a justing and repairing 1t is very desirable to mount all the coils m close proximity in a a ditliculty known variously as back'iring or cross firing. Where the apparatus is used on a m'otor vehicle the trouble is called bucking land is annoying and sometimes very dangerous. The trouble is manifested by the cylinders firing out of order or se v quence and is due I believe to magnetic andy primaries and static induction between the 'secondaries of the coils.

This however has Given rise to.A

being brid ed o1l shunted across the vibrator It is my object to prevent such trouble and to insure a perfectly regular and orderly acso as to prevent any interference between the primaries and secondaries of adjacent coils. The design or shape of these shieldinv plates is unimportant but they preferably orm an open circuit around the coils.

The drawing shows a section of casing with four units,.one of which is in section, and all are arranged in a diagram with a four cylinder four cycle motor.

The cylinders 1, 2, 3 and i are provided with the usual valves and pistons connected to cranks 10, 20, 30 and 40. The igniters 11, 21,v 3l and 4l have one terminal of each grounded on the engine frame and the other terminals connected to the terminals 12, 22,

A32 and 42 in the bottom of the casing 5. The

casing preferably has a center partition 50 which strengthens it and divides it into two compartments, The battery or source of current'- is grounded at 60 on the engine frame andconnected to terminal 61 inthe casing...- It is often desirable and, in fact, customary', to rovide an additional battery such as 62 an a switch with the contact 63 and 64 and vswitch arm 65,'"s'o that either battery maybe 'thrown into or out of circuit readily. Y

A circuitclosen or switch is provided, which is driven at arate proportioned to the speedofthemotor, as is customary, and whichyhas a vrevoluble member 7, grounded 'at 70 on lthe engine frame. The contacts 71,

472, 73 and 74 are connected to the terminals 51, 52, 53 and 54 in the casing.A Each of the coil boxes 81,62,v '83 and 84v 'is'preferably independently removable from the casing and contains a primarywin'ding P, a secondary winding S and a condenser C, the latter terminals and ``V.:The primaries have terminals P', P2, P3, and Pf on the exterior of the' boxes which-'engage the contact strip other terminals of the coil-windings in each box are connectedy to the bridge I5. The armatures, such as V, are connected to terminals C, C2, C3 and C* on-the exterior of the boxes which engage the contacts 55, 56, 57 and 58 in the casing which are connected to the terminals 5l, 53 and 54.

In the position shown in the drawing, the primary circuit may be traced from`battery 6 to terminal 6l, contact strip 66, contact P, primary winding P, bridge B, vibrator V, contacts C and 55, terminal 5l, contact 71, circuit closer 7, ground to 60 switch 65, contact 63 to the battery. The secondary circuit may be traced from the secondary winding S, terminals S and l2, igniter ll, through engine frame to ground 70 circuit closer 7, contact 7l, terminal 51, contacts 55 and C, armature V and bridge B back to the secondary.A The charge in cylinder l is thus ignited. It is customary to fire the cylinders in the order of l, 2, 4 and 3 and the circuits as shown are so ordered, the circuit closer rotating to the right, so as to successively complete the circuits through the coil boxes 81, 82, 84 and 83. It is obvious that contacts 72 and 74 might be interchanged so that the order of firing would be l, 4, 2 and 3, the valves being properly set.

Sometimes the charge in cylinder 2 which, as shown and described, is supposed to follow cylinder l at 180, although uncompressed is ignited at the same time as cylinder l. I have been able to prevent this by eliminating or reducing the induction eii'ect of the coils in box 8l on the coils in box 82 by means of a soft iron plate or shield placed between the coils. Preferably I place a plate or sheet such as 9 and 90 on each side of each coil within the box which is customarily of wood. There is then no danger of the cross induction, no matter what the position or arrangement of the boxes inthe casing. The same diiiiculty of back or cross firing is encountered in four cycle engines of moreV than four cylinders and may be avoided by the use of my invention; so also in engines of the two cycle type and two or more cylinders,

lthe cross-tiring7 may be avoided by inductivel'y insulating the coils for the different cylinders by one or more shields as described. I wish it clearly understood that I-consider my invention vin its broad sense to cover the use of any suitable material preventing cross-induction anduntimely firing. Experiment with a system may show that the cross firing occurs only in one cylinder, in which case it will. be only necessary to shield the coil for that cylinder on the side from which the trouble comes.

l/Vhat I claim is:

l. Induction apparatus for an ignition system comprising, a plurality of adjacent coils, each consisting of normally open circuit primary and secondary windings and a shield to prevent induction between the adjacent secondary windings.

Induction apparatus comprising a plurality of' coils, each consisting of primary and secondary windings, a vibrator for each primary and a metallic member between the coils` each secondary.

3. Induction apparatus comprising a plurality of coils -arranged in close proximity to one another'and each having normally open circuit primary and secondary windings and adapted to be brought into operation in a predetermined sequence and means for preventing the induction of currents in one secondary by the influence of an immediately adjacent secondary.

4. Induction apparatus for ignition systems comprising a plurality of coils having normally open circuit primary and secondary windings, and an iron plate between adjacent coils to prevent troublesome interference.

Induction apparatus for ignition systems comprising a plurality of coils and an open circuit shield between adjacent coils to prevent interference.

6. Induction apparatus for ignition systems comprising a plurality of ,coils and a shield between adjacent coils and projecting above and below the ends thereof to prevent cross induction.

7. Induction apparatus comprising, a'casing, a plurality of independently removable coil units mounted therein and a shield to prevent interference between adjacent units.

8. Induction apparatus comprising a casing, a partition dividing said casing into two compartments a plurality of coil units in each compartment yand a shield to prevent interference between the units in a compartment.

' 9. Induction apparatus comprising a casing, a plurality of coil units'v removably mounted therein and each consisting of a box, primary and secondary windings and a shield on at least one side thereof inside said box to prevent interference. l j

j l0. Induction apparatus for ignition systems comprising, a plurality of coils and one or more sheets of iron between adjacent coils leaving at least one side of each coil exposed. y

11. Induction apparatus comprising a plurality of coil units each having shields on its opposite sides to prevent interference and leaving at least one side exposed.

l2. An induction coil for ignition systems comprising primary and secondary windings, and a sheet of iron on one side tlierof leaving at least one other side expose 13. An4 induction coil for ignition systems con'prising, primary and secondary forming a local magnetic shield for i windings and shields on tWo sides of said windings, a vibrator, a condenser shunted 10 coilvoniy to prevent interference. across the vibrator contacts and an open 14. An induction coil for ignition systems circuit shield arranged on at least one side comprising, a vibrator, primary and secondthereof to prevent interference.

ary Windinvs and a shield on one side thereof to prevtent interference and leaving at BURTON L LAWTON' least one side exposed. Witnesses:

15. An induction coil for an ignition sys- L. T. FLLER,

tem Comprising, primary and secondary V. M. KOAREMAN. 

